Fuel Pressure Regulater worth it ?
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If you don't know what it's for, why did you buy it?
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it's a tuning tool. It will help if you need to increase your fuel delivery to achieve the correct air fuel ratio at idle or over the entire rpm range. The B&M sits on top of your stock regulator and is a dead head type of FPR not a bypass type, meaning that it uses a spring loaded screw to pinch the passageway leading into the fuel rail. There is a vacuum line attached to it. The stock FPR is on the driver side end of the fuel rail. Your stock range of FP is 40-47 psi with the vacuum line off. Then re-attach the line. Start at 43 psi...and see if it's too rich or too lean by reading your spark plugs. Have you purchased the B&M fuel pressure gauge that is mounted on top of the fuel filter or on the FPR?
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BTW you never want to exceed 25% over the max stock setting range or you'll decrease the life of your injectors and throw off the fuel map program calibrations on the ECU.
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it's too late. he's already bought it. the horse is out of the barn and closing the door ain't gonna work.cubedgsr on Aug/06/02 said:
the FPR is a tuning tool. You can use it to lean out as well as to richen...it's a fallacy to think you just go in one direction, especially at idle.
It's a good tool to have in your pocket for now until you get other mods. Just remember the 20-25% rule for pushing how high you can go. So 25% above your max which is 47 psi is 59 psi.
To see how much of a change in fuel flow rate that is you use this equation:
SQRT (new FP/old FP) x injector flow rate
SQRT means square root.
your current stock injector flow rate is 240 cc/min at 42 psi.
SO if you turn the FP up to 59 psi,
SQRT (59/42) x 240 = SQRT (1.4) x 240 = 1.18 x 240 = 284 cc/min.
That's heavily pushing the injector. When you pinch down of the fuel system using a dead head type FPR, you increase how much the fuel pump must push against to pump the fuel up to the fuel rail. So not only are you making the injectors work harder, you are making your fuel pump work harder and heat up. At some FP point you can overheat the fuel pump as well and cause it to fail. Getting no fuel to the engine isn't a pretty site...it's called lean out detonation. Do not exceed that 20-25% rule.
Here's the flow rate on an ITR/GSR/Si fuel pump (the LS fuel pump is smaller) when you increase the FP:
as you can see the flow rate tails off on the priming end of the FPR before the fuel rail and injectors as you crank up the FP to get more flow at the injector.
If you go 50% to 70 psi?: you risk fuel pump failure, you have thrown the fuel calibrations out the window for the ECU fuel map programs and so the input readings to the ECU are meaningless to it, and your injector life will be cut in half...maybe 6-8 months. At $400/set they ain't cheap. Neither is a fuel pump and neither is an engine leaned out and detonated.
Use the plugs to tell you whether you should go up or down on the FP. You should read the plugs at wide open throttle (WOT)...don't read them just at idle. Do a full throttle or WOT run at the local track's test & tune day, pull off immediately to the side where it is safe to do so, shut the car down immediately and don't let it cruise around back to the starting line or idle, and then read the plugs right there and then...it'll tell you at full throttle whether you need to up the fuel or go down on it.
If you just crank it up for the hell of it, you will likely run too rich which is slower/less hp but safer than going lean.
We use the FPR for taming the idle of wild cams and to give us an extra margin of fuel delivery across the board without having to go to the next size up on the injectors (as long as the injector duty cycle or the time they are open does not exceed 80-90%).
cheers
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of course, a wideband o2 sensor at a dyno can tell you the exact air fuel ratio and whether you need to increase the FP or lean down further as well....instead of a WOT run and reading the plugs...
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I stand corrected....kelly on Aug/07/02 said:
Here's the B18 stock FPR from the Helm's Manual:
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I've been a moderator on 4 honda boards for 7 years...lets just say I have a large library....
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A fuel pressure regulator is a tuning tool as specified above, you will need one with a simple bolt on as a CAI for tuning. More so needed needed with a Turbo or super charged set-up. (like my set-up) Need to adjust your fuel pressure, best done on a dyno.
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